(a) Field of the Invention
The present invention relates to a method and an apparatus for configuring a transmission time interval in a mobile communication system, and more particularly, to a method and an apparatus for configuring a transmission time interval capable of supporting services having requirements for lower latency of less than 1 ms between a base station and a terminal in a mobile communication system.
(b) Description of the Related Art
A communication system such as an LTE (long term evolution) or LTE-advanced can employ a transmission time interval (TTI) for transmission of data between user terminal and a base station. Within each TTI, data packets are delivered to the L1 layer from the L2 layer and transmitted over the radio interface to the L1 layer of a receiver.
Upon reception of a data packet, the receiver makes an attempt to decode the data packet and informs the transmitter about the outcome of the decoding operation through a single acknowledgement bit indicating whether the decoding was successful or if a retransmission of the data packet is required. If the decoding fails, the receiver notifies the transmitter by sending a negative acknowledgement (NACK). In response to an NACK, the transmitter retransmits the same data packet. Such the HARQ operation is performed in a TTI unit of length 1 ms. A latency across the radio access link is determined based on times required for data transmission, reception and HARQ procedure.
In the LTE, the TTI corresponds to one subframe of length 1 ms. Accordingly, in the case of LTE, the TTI corresponding to one subframe of length 1 ms may not support services having requirements for lower latency of less than 1 ms.